Automatic stoker.



11. J. AMES. AUTOMATIC S'IOKER. APPLIOATON FILED AUG. 6, 1910.

. Patented Feb. 2v, 191.2.

SHEETS-SHEET 1 a e i D. J. AMES.

` AUTOMATIC STOKER.

APPLICATION FILED AUG. S, 1910. Y

` 1,018,690, .Patented Fe10.27,1912.V

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D. J. AMES. AUTOMATIC STOKBR.

APPLICATION FILED AUG.6,1910.

l L'GlSQG. Patented Feb;27,1912.

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DAVID J.- AMES, or AUSTIN, MINNESOTA.

To all whom if may concern."

Be it known that I, DAVID J. AMES, a citizen of tlie" UnitedStates,residing at Austin, inI the county of Mower and State of Minnesota, haveinvented certain new and useful Improvements in Automatic Stokers; and Ido hereby declare the following to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it'fappertains to make and use thesame'.

My invention has for its special object tov 1provide an improvedmechanical Stoker, and

to this end it. consists of the novel devices and combinations ofdevices hereinafter de- :scribed and defined in the claims.

` frdnt elevation of an ordinary boiler tire rbox having my inventionapplied thereto some parts being broken away. Fig. 2 is a detail viewpartly in elevation and partly in vertical section and withl some partsbroken away showing a variable speed mechanism for operating the stokcrproper. Fig. 3 is a view partly in plan and partly in horizontal sectionand with some parts broken away showing my improved stoker and itsactuating mechanism applied in connection with th'e grates of the firebox. Fig. 4 is a detail in section taken approximately on the line mj*of Fig. 3. Fig. 5 is a side elevation showing the stoker applied to thegrate and other parts of the furnace being removed. Fig. G is atransverse vertical section taken through the grate on the line of o1 ofFig. 5. Fig. 7 is a plan view of the fuel feed screw, and Figs. 8 and 9are sections` taken respectively on the lines :as fr and .5.119 az ofFig. 7.

0f the parts of the furnace the numerall indicates the masonry walls andthe nu* meral 2 a door which opens into the tire box above the grates.So far as my invention concerned, the grate may be of'any suitable form,but as shownand preferred it is made up..of a rectangular toothed lixedstructure. 3, and la multiplicity of rocking toothed bars 4. The lixedgrate structure 3 is hori- Lzontally disposed and Vits teeth areinterlapped with the teeth of the rocking grate bars 4, the latter attheir ends being det-ach- Speeication of Letters Patent. Appli-cationfiled August 6.1910. Serial No. 575,951.

At the transverse center the fixed gratel Parenteel ret.' 2r, i912.

structure 3 is formed with a large longi- .y

tudinally extended fuel admission passage irthat is in communicationwith the delivery end of a fuel supply spout 6. This fuel spout 6 ispreferably a eas-t structure havin at its extreme outer end a detachablehead connected thereto, as shown, by short nutted bolts 8, best shown inFig. 5. The outer and receiving end of the spout 6 is in communicationwith the lower end of a fuel supply hopper 9; one wall 9a of which isinclined at an angle of approximately 45 degrees, and terminates at apoint substantially di rectly above the axis ofthe said spout 6. Thislatter feature is important and is for a purpose which will behereinafter noted. The delivery end of the spout G is tapered so thatits bottom rises quite abruptly throughout that space underlying thefuel delivery passage 5 of the grate The rock ing grate bars 4 at theirintermediate portions. are provided with depending arms la that areconnected by link l0. O ne of the arms 4e is also connected by a shortlink il to the depending arm l2 of a horizont-al rock shaft 123 mountedin suitable bearings 11i on the spout G and provided at its front endwith a rigidly secured arm l5, the pur pose of which will hereinafterappear.

lVorking within the feed spout 6 is a spiral feed screw of novelconstruction. indicated as an entirety by the numeral 16. Between thepoints marked a-Z)` (Fig. 7) the spiral blade of this feed screw 1G isgiven a constantly increasing pitch or travel, for a highly importantpurpose presently to be described, and between the points marked p5 o-dIthe said feed screw is formed in ap proximately. flat contiguous bladesections 16a' that are obliquely set with adjacentl sections reverselyinclined. The blade sections 16a work in that portion ofthe spout 6which underlies the fuel delivery passage The feed screw 15 ispreferably cast integral with an axial shaft, the inner vend of which isjournaled in the seat formed in the delivery' end of the spout 6 belowthe grate. The outer end of the 'shaft of the said feed screw ispreferably square at 16b and is extended outward through the -head T ofthe spout G. 'lfhe said head 7 and the flanged end of the spout (S arerecessed vto afford la seat for a coperatingworml? worm` gear 18;Y Thesaid gear'18is seated.V

on the square end -16b ofthe feed screw 'shaftwhile the worm 17 issecured to one ve'n`d"of an operating shaft 19. One end o f theshaft v19 is journaled in a divided'seatfor'medin the depending portions of thehead/ and flanged upper end of the spout 6, and the.

other end of the said shaft 19 is journaled in a gear case or housing 20shown as rigidly secured to the floor in front ofthe furnace and at oneside ofv the fuel supply hopper 9. Preferably the 4housing 20 is aYdivided or two part structure the sections of which are rigidly securedby suitable bolts and one section vof which in Fig. 2 is removed.

Within the housing 20 the shaft 19 carries a pluralityof spur gears 21of varying. diameter.

spur gears 22 that `are normally loose on a. shaft 23 that is extendedthrough the hubs The gears 21 are in mesh with thereof, and is johrnaledin the housing 20 and'with freedomfor endwise movements.

' The gears 21 and the gears 22 are in reverse conical larrangement sothat by coupling the drivingv shaft 23 ,to different members of thegears 22 a variable speed transmission mechshown, a -sprocket 26connected to the said shaft 23 by a long key 27. The shaft 23 moves'through the sprocket 26 and-the hub ofthe latter is provided with agroove 28 that is engaged by a forked bearing 29 `rigidly secured to thehousing 20. rlhe said bearing 29 holds the sprocket against lateralmovements, but'permits the same to freely rotate. A sprocket .chain 25runs over the sprocket 26.

The shaft 23 is adapted to be given -axial movements and to be set inits different operative and inoperative positions preferably by means'of the rack bar 30 thatis mounted in thetop portion of the housing 20-and is provided with a depending end 31 of4 which. the correspondingend .on the. said shaft 23 is swiveled. rI he teeth of the rack 30 areengaged by a spur pinion 32 that is 'rotated and mounted in a suitableseat formed within the housing 20 and is provided with a projectingshaft 33 which in practice will be equipped with an operating crank 34.The rack 30 is adapted to' be locked in its various positions by a lockdog 35 pivoted on top of the housing 20 and engageable with notclr`36`in the top of .the said rack 30,

veral spaced perforations Y cated variable distances from the axis oflthe said crank head and adapting lthe lower end of the lock 38 to be.connected to said crank'disk for variable thrust `orcrank actions.

that the surface of the'blad'eslaof the feed screwin a radial directionare straight or approximately flat; and by reference to By reference toFig, 9 it will be noted.,

Fig. 8 it will be noted that the operative surface of the main body ofthe feed screw in a radial direction is made concave. Furthermore, theconcavity of the working face of the feed screw is such that itsgreatest depression is at the central portion of the said working face.This latter feature particularly is of verygreat importance, as will bepresently more fully explained.

The coal or similar fuel which is to be fed to the furnace is deliveredin a suitable way into the hopper 9. The direction or rotation ofthefeed screw 16 is indicated on )Figy 4.

by reference to which it will be seen that the spiral blade of the feedscrew cuts off the fuel from the bottom ofthe hopper against the sharpoverlying edged portion of the inclinedAv bottom section 9EL of vsaidhopper, in such manner that the body of fuel in the hopper is not forcedwith anyconsiderable pressure against the side of the hopper.l Coal dustor screenings are very largely and quite generallyused in furnacesemploying automatic stokers, and this fo-rm of fuel when used by a feedscrew through a spout has'a very great tendency'to pack tight in thespout and produce such .friction that it is practically impossible tofeed-the material as far as usually required to deliver thesame properlyto the furnace grates. In fact, it

frequently happens that very strong feed screws are twisted off in anattempt to deliver t-he fuel which has become tightly packed in the feedspout. It of course also follows that very great 'power is required tooperate the feed screw even under-the most favorable conditions heretoprovided for.

l My improved feed screw has been thoroughly tested in actual use andseems to be Aa solution of the problem of making a feed screw. operativefor thel purposes above stated. Two highly important features contribute'to this result. important of the two is the arrangement of the spiralfeed blade with an increasing The iirst'and more pitch or travel in the`direction of the feed of the material. ral `space of increasing widthand conducting capacity, in the direction of the travel of the materialand therefore constantlyr relieves the material pressure whichr would,with a feed screw of constant pitch and di- 'ameter,A be accumulativeand increasing.

secure ythe desired result, and it is further important that the'workingface of the feed screw have its greatest conca-vity, or depression,approximately at its central portion,`

that is, about midway between its peripheryand the line of its junctionwith the screw shaft. This gives the vdesired relief from both outwardpressure of the material being fed against the spout, and against theshaft of the screw. A third important novel feature of the feed screw isthe arrangement of the alternated and approximately dat blade sectionsin space or capacity through whichthe fuel is delivered from the feedspout upward through the bottom of the grate. ward on to the top 'of thegrate and insure good and proper `distribution of the fuel over theupper surface ofthe grate.

By adjustments of the shaft 23, inrespect. vto the gears 22, and alreadydescribed, the

rate of rotation of the feed screw may be varied, without changing thespeed of the driving sprocket 26 or the primary source of power, andthis as is evident provides for j a variable supply of fuel to thefurnace.

Through the described connections 37, 38, l5, l2, l1 and 10the rockinggrate bars will be slowly but constantly moved so as to keep the properamount of ashes worked' through the grate and into the ash pit. With theadjustable connection of the link 38 to the arm 15 and crank"head 37makes it possible to vary at will,I the extent of oscillatory movementimparted to the rocking grate bars, at'each complete vibration. The num-`ber of vibrations, per unit of time of the rocking grate bars, varieswith the speedof the rotation of the feed screw, but the grate cleaningaction may be independently varied by the adjustmentsjust noted. .The efThis in itself gives a spi- These blade sections lift the fuel upthebottom of said grate, and a feed screw rotatively mounted in said feedspout and provided at its'delivery or inner end with flat contiguous andconnected obliqueblade sections, the adjacent-obliqueblade sections`'being reversely inclined, and the. saidV oblique sections beingarranged to work in- 70- the-space through which the fuel is deliveredupward from the said feed spout through said grate.

2. The combination with `a furnace and a I grate therein, of a feedspout leading into' -said'furnace and opening upward through the bottomof said grate, anda feed screw rotatively mounted in said feed spout,the spiral blade of'v which screw throughout the main body portionthereof having` aprogressively increasing pitch in the direction of thefeed of the .material into the furnace, the wbrking face of said bladebeingconcave in cross section, andthe said feed screw at the point ofdelivery of the fuelupward through said grate being provided v,withcontiguous andconnec-ted fiat blade sections, the adjacent members-ofwhich are inclined in reverse directions, and. the said' spiral and fiatblade lsections being cast integral with said feed-screw and the 'firstvof said Hat blade sections being integrally united with the spiral blade-of saidscrew.4

3. The combination with a'furnace and .a grate therein, said gratehaving rocking sections, of' a feed spout eXtendin-ginto said furnaceand arranged to deliver the fuel upward from the bottom of said grate, afeed screw working in said feed spout, a powerl driven variable speedtransmission mechanism for driving said feed screw, and connections fromthe said variable speed mechanism for oscillating the said rocking gratesections, the said grat-e operating connec" In testimonywhereof I aflixmy signature in presence of twowitnesses.

'Witnesses: Y i l R. A. CARMICHAEL, S. A. SMrrir i DAVID J.I autres.4` l

